Compounded oil



Patented Feb. 15, 1944 COMPOUNDED on.

Arthur L. Lyman, Berkeley, and Lloyd H. Mulit, Richmond, Califi, assignors to Standard Oil Company of California,.San Francisco, Cali l'., a

corporation of Delaware Q -No Drawing. Application January22gi'l940; Serial No.315, 034

' Claims. (01152-485? This invention relates to'a new and usefulcomposition of matter and involves, .a composition comprising a hydrocarbon oil and a new combination of stabilizing ingredients. More particularly, the invention pertains to a viscous hydracarbon oil containing a metal alcoholate and an oxidation inhibitor. 1

The production of improved hydrocarbonpils, and particularly of lubricating oils having desired characteristics, has been the subject of extensive research. Generally speaking, the compounding of hydrocarbon oils .to obtain desired characteristics involves empirical phenomena and the action of untested combinations of difierent types of compounding agents cannot be predicted,

A characteristic which has been the subject of extensive investigation is the tendency of hydrocarbon oils to deteriorate or partially decompose and oxidize when subjected to high temperatures.-

This deterioration is evidenced by the deposition of adhesive deposits on hot metal surfaces over which the hydrocarbon oil may flow. It is im--' I portant that resistance to, such deterioration be this type of deterioration during'lubrication of in-' ternal combustion engines is the formation of varnish on the pistons and cylinder walls, and in engines of the Diesel type a pronounced tendency of the oil toc'auselor permit the sticking of piston rings.

The crankcase lubricant in internal combustion engines is {Subjected to extremely severe operating conditions,"andin engines of the Diesel type the lubricant encounters in the piston ring zone temperatures of from approximately"425- to 650 F. and pressures from the oxidizing combustion 8517750 to 1150 pounds per square inch. in item "especific aspects the present inventiorris-jdir ted to the improvement of hydroting-oils-byimparting' thereto increased res stance to deterioration by heat at high temperature levels-in 'the' order of those above-mentioned. It has been observed that high temperature oxidation inhibitors, i; e. oxidation inhibitors effective at temperatures as high as 300 F. or above, in combination with metal alcoholates impart to hydrocarbon lubricating oils a number of highly desirable properties and improve the lubrication and operation of internal combustion engines. More particularly, it has been discovered that a lubricating oil containing both a metal alcoholate and a high temperature oxidation inhibitor permits longer periods of op- :ration oiengines without the necessity of major.

o'verhauls heretofore occasioned, ;by stuck piston rings, wear of pistons and? cylinder walls, or in some instances corrosion -of bearing metalalloys.

The broader aspects" of the invention-involve the' 'discovery that oxidation inhibitors and metal alcoholates cooperate to give new results in hydrocarbon oil compositions. Hydrocarbon oils containing this combination of ingredients have greater stability under various operatin conditions .than'" dof oils containing "either of these types of ingredients alone. For example, the same improvement is not obtainable with 0.75% of a metal alcoholate or with 0.75% of an antioxidant in a lubricating oil as is obtained with 0.50% of the 'metal alcoholate and 0.25% of the same antioxidant'in the same lubricating oil. Although it has been discovered that oxidation inhibitor in general cooperate with metal alcoholates in the above unpredictable manner, the mechanism of this cooperation has .not been established and the inventors therefore refrain from any attempted explanation of the phenomena-observed. v

I "it should be noted that oxidation inhibitors or antioxidants which are efiective at low temperatures to inhibit oxidation in hydrocarbon oils may not be effective at higher temperatures and under more'severe operating conditions, such as those which lubricating oils encounter in the piston ring belt of internal combustion engines such as Diesel engines. Although the broader aspects of the invention are not so limited, it is preferred to utilize in combination with metal alcoholates high temperature oxidation inhibitor effective above 300 F., and preferably effective to inhibit oxidation of lubricating oils containing metal alcoholates at temperatures in the range of 400 to which fall within the scope of.this invention are represented by the type formula:

M- x c-'--R where Mr'epresents a metal,. Xindicatesoxygen or sulfur, C a non-benzenoid:c arbon atom, R an organic radical of hydrocarbon structure, and n is from one to the valence of the metal. M is a metal such as those previously listed. By nonbenzenoid carbon atom it is intended to designate a carbon atom which is not, in the nucleus of a benzene ring, although attachment to a henzene ring is not precluded. Examples of radicals of hydrocarbon structure which R represents are: alkyl, aryl, alkaryl, aralkyl and cyclic non-benzenoid. R need not necessarily be a pure hydrocarbon radical but may contain other substituents, such as oxygen, halogens, nitrogen, and the like. Acyclic radicals are preferred, and the entire compound preferably contains at least ten carbon atoms.

Examples of preferred alcohols utilized to form the metal alcoholate are the higher alcohols, such as amyl, hexyl, heptyl,octy1, nonyl, decyl (lauryl), dodecyl, tetradecyl, hexadecyl (cetyl) octadecyl, ceryl, myricyl, and unsaturated alcohols, such as lanolin alcohol. The following are metal alcoholates of these alcohols which are embraced by this invention: sodium amylate, sodium hexylate, sodium heptylate, sodium octylate, sodium nonylate, sodium decylate, sodium dodecylate, sodium tetradecylate, sodium hexadecylate, sodium octadecylate, sodium cerylate, sodium myricylate, sodium lanolate (sodium salt of lanolin alcohol), calcium amylate, calcium hexylate, calcium heptylate, calcium octylate, calcium nonylate, calcium decylate, calcium dodecylate, calcium tetradecylate, calcium hexadecylate, calcium octadecylate, calciumcerylate, calcium myricylate, calcium lanolate (calcium 'salt of lanolin alcohol),

magnesium amylate, magnesium hexylate, magnesium heptylate, magnesium octylate, magnesium nonylate, magnesium decylate, magnesium dodecylate, magnesium tetradecylate, magnesium hexadecylate, magnesium octadecylate,,

magnesium cerylate, magnesium myricylate, magnesium lanolate (magnesium salt of lanolin alcohol), barium amylate, barium hexylate, barium heptylate, barium octylate, barium nonylate, barium decylate', barium dodecylate, barium tetradecylate, barium hexadecylate, barium octadecylate, barium cerylate, barium myricylate, barium lanolate (barium salt of lanolin alcohol), aluminum amylate, aluminum hexylate, aluminum heptylate, aluminum octylate, aluminum nonylate, aluminum decylate, aluminum dodecylate,

aluminum tetradecylate, aluminum hexadecylate, aluminum octadecylate, aluminum cerylate, aluminum myricylate, and aluminum lanolate (aluminum salt of lanolin alcohol).

Additional alcohols are: cyclo-alkyl alcohols like cyclohexanol, and aralkyl alcohols like benzyl alcohol, as well a acyclic thioalcohols, cycle-a1- kyl thioalcohols, and aralkyl thioalcohols, in which sulfur replaces the normal oxygen of the alcoholic group. Examples of thioalcohols are the mercaptans, such as amyl mercaptan, hexyl mercaptans, cyclohexyl mercaptans and the like.

Metal derivatives of organic compounds capable of forming the enolic structure also may be utilized. Such derivatives of the enolic compounds contain the group represented by the type formula:

where R represents an organic radical, preferably a hydrocarbon group, and M represents a bond to a metal atom.

The metal alcoholates of this invention may be prepared by any suitable method. For example, sodium alcoholates may be prepared by reaction with sodium metal, the calcium alcoholates by reaction of the alcohol with calcium carbide, and the aluminum alcoholates by reaction with metallic aluminum catalyzed with a crystal of iodine.

As has been previously indicated, the invention in its broad aspects embraces hydrocarbon oils containing generically antioxidants for hydrocarbon Oils in combination with metal alcoholates. Many antioxidants for hydrocarbon oils are known, and the following types are mentioned for purposes of illustration:

(1) Oil-soluble hydroxy compounds like 'polyhydroxy phenols, condensed ring phenols, alkyl substituted phenols, and naturally occurring inhibitors which may b extracted from fats and petroleum oils;

Nitrogen compounds such as aryl amines (diamlnes. dlaryl amines),. nitroso amines, cyclo-aliphatic amines, and condensation products of aldehydes or ketones with aromatic amines;

oxygenated organic compounds comprising aryl ethers, ary1 ketones and alkyl ketones;

Esters of certain types of acids, namely, oilsoluble esters of alpha and beta hydroxy carboxylic acids in which a carboxyl group is not more than two carbon atoms removed from a hydroxy group, esters of polycarboxylic acids having two carboxyl groups no more than two carbon atoms apart, and esters of carboxylic acids having an unsaturated carbon-to-carbon bond conjugated with the carboxyl group;

Oil-soluble organo-metallic compounds of metals selected from groups 11, III, IV and V of Mendeleefis Periodic Table;

Sulfur, selenium and tellurium compounds (other than compounds in which the sulfur, selenium and tellurium are in a carbocyclic ring), such as ary1 mercaptans, sulfides, disulfides, polysulfldes, aryl thioesters, seleno ethers, telluro ethers, alkyl sulfides, alkyl disulfides, alkali metal sulfonates, and alkaline earth salts of sulfonic acids;

Miscellaneous ring compounds comprising mercapto benzithiazole, oxazines, phenthiazine, indane and acridane; 1

Organic phosphorus compounds comprisin oil-soluble phosphines, esters of phosphorous acid and esters of phosphoric acid;

(9) Alkaline earth organo-borates and alkaline earth organo-arsenates.

this more rigid requirement, and many-of; them are therefore not fully equivalent to the preferred species utilized in the present invention. .IExamples of types of high temperature oxidation inhibitors 'for hydrocarbon oils comprise metal salts of substituted acids of phosphorus, certain oilsoluble esters of carboxylic acids containing an active group, alkali metal sulfonates, alkaline earth metal sulfonates, alkaline earth organoborates, alkaline earth organo-arsenates, and naturally-occurring inhibitors which may be extracted from mineral oil fractions. By the terms 2,341,565 alkaline earth organo-borates" and "alkaline.

earth organo-arsenates" it is intended to designate alkaline earth salts of acids of boron or acids of arsenic which contain an organic substituent. The organic substituent may be an alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid group. Alkyl substituents are at present preferred.

The following comprise examples of inhibitors of the ester type having the above-mentioned active groups:

Di-ethyl tartrate, di-butyl tartrate, di-amyltar-' trate, di-isoamyl tartrate, di-benzyl tartrate,

di-octyl tartrate, di-lauryl tartrate, amyl lactate, octyl lactate, tri-iso-amyl citrate, di-amyl mucate.

The active grouping in these compounds comprises a hydroxyl group in the alpha orbeta position relative to the carboxyl group. These types of compounds may be represented generically by. the following structural formulae:

karyl, aralkyl or cyclic non-benzenoid group.

A second series of inhibitors of the ester type having anactive group comprises oxalates, malomates and succinates of ethyl, propyl, butyl, amyl and the like alcohols. The neutral esters ofthese pclycarlooxylic acids are preferred.

The active groupingin the abovesecond series of esters comprises two carboxyl groups no more than two carbon atoms apart and may be represented generically by the following structural formulae:

l? 9 Ri-o-o-'c -o-R2 o H o A third series of esters containing an active group comprises ethyl, propy1, -butyl, amyl and octyl esters of maleic', fuma'ric, acrylic and crotonic acids. The active grouping in these compounds comprises an unsaturated carbon-to-carbon bond conjugated with the carboxylgroup. These types of compounds may be represented by the following structural formulae:

H H o sleet-OR.

in which R1 and R2 may be alky l, aryl, alkaryl, aralkyl or cyclic non-benzenoid groups.

Metal salts of substituted acids of phosphorus this type, which may be utilized which is effective at high temperatures in the combination of this invention. Metal salts of comprise salts of metals selected from groups I, II, III, IV and VI of Mendeleeffs Periodic Table of the Elements. Specific examples of such metals are aluminum, cadmium, barium, strontium, chromium and magnesium. Salts of cobalt, nickel, zinc, sodium, potassium and amonium comprise additional examples of com pounds falling within the broader aspects of the invention. The following'comprise specific examples of metal salts of substituted acidsof phosphorus, illustrating this type of oxidation inhibitor: cetyl aluminum spermol phosphate, aluminum oleyl phosphate, aluminum "spermenyr phosphate: aluminum di-(cyclohexanyll phosphate, aluminum (cetyl phenyl) phosphate, aluminum di-. (amylphenyl) phosphate, aluminum di-stearogiyceryl' phosphate, aluminum (tetra-chloro-octa-decyl) phosphate," aluminum di(6-chloro, 2- phenylphenyl) phosphate, aluminum di- (3-methaluminum iauryl phosphate, aluminum 1 yl, 4-chloro phenyl); phosphate, aluminum naphthenyl phosphate, calcium laurylphosphate, calcium cetyl-phosphate-calcium octadecyl phosphate, calcium spermol oleyl phosphate, calcium spermenyl'phosphate, calciuin, di-(cyclo-hexanyl) phosphate, calcium (cetyl phenyl) phosphate, calcium di-(amylphenyl) phosphate,v calcium 'di-stearo-glyceryl phosphate, calcium (tetra 'chloro octadecyl) phosphate, calcium di- (6-chlo ro, 2-phenyl phenyl) phosphatef calcium' di-(3-methyl, 4-chloro phenyl) phosphate calciumi naphthenyl phosphate, chromium .lauryl :phosphatc, chromium cetyl'phosphate', chromium octadecyl phosphate, chromiumffspermol phosphate, chromium oleyl phosphate, chromium ffspermenyl phosphate.

chromium di-(cyclohxanyl) phosphate, chromium-cetyl phenylphosphate, chromium di-tamyl-phenyl) phosphate;-J'chromium di-stearo-glyceryl phosphate, chromium tetra-chloro-octadecy] phosphate, chromium." 'di(6-chloro, Z-phenyl phenyl) "phosphate, chromium dil 3-methyl, 4- chloro phenyl) phosphate, chromium naphthenyl phosphate, barium lauryl-phosphate, barium cetyl phosphate, barium octadecyl' phosphate, barium spermol phosphate, barium oleyl phosphate, barium :spermenyl phosphate, barium dicyclohexanyl). phosphate, barium cetyl phenyl phoslum di-stearo-glyceryl illustrate another type of oxidation inhibitor methyl, naphthenyl' phosphate, as well as corresponding phate, barium di-(amylphenyl) phosphate, barphosphate. barium tetrachloro-octadecyl phosphate,- barium di-(6-chloro, 2-phenyl phenyllphosphate, barium (ii-('3- 4-chloro. phenyl) phosphate, barium sodium, potassium, magnesium and ammonium salts. Metal salts of substituted acids of phosphorus illustrated by the above compounds comprise salts of substituted oxy-acids of pentavalent phosphorus of the following type formulae:

o a 0:1 0 R on where R and R may be alkyl, aryl, alkaryl, araliron,

phosphate, alumlnum-octadecyl phosphate.

phosphate, calcium oxy-acids of phosphorus which may be used in forming the metal salts of the present invention are as follows: on

u\ on Pliosphonic acid Mono-ester of phosphonic acid P-Oll l Phospbiuic acid In all'of the above formulae R. and R maybe alkyl, aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups.

Each and every one of the above antioxidants may be utilized in combination with metal a1- coholates in hydrocarbon oils according to the present invention. Hydrocarbon oils containing both a metal alcoholate and an oxidation inhibitor of the above types have new and unpredictable advantages illustrated by the following discussion and data:

A lubricating oil containing a metal alcoholate and a high temperature antioxidant effective above 300 F. in the presence of the alcoholate is more efficient in the lubrication of internal combustion engines than is an oil containing either of the components alone. In engine tests it has been found that metal alcoholates permit the formation of a gum or varnish on portions of the pistons after prolonged periods of operation. Various of the metal alcoholates have also been found to impart corrosiveness toward copper-lead or cadmium-silver alloy bearings to lubricating oils containing the same. A high temperature oxidation inhibitor, such as calcium cetyl phos-' phate, overcomes or minimizes these disadvantages. On the other hand, a calcium cetyl phos phate permits thermal decomposition of the lubricating oil and some deposition of carbon in the top piston ring grooves under severe conditions of operation. The metal alcoholate minimizes this disadvantage of the high temperature oxidation inhibitor. Thus by using these two types of ingredients in combination in lubricating oils, each of which has one or more disadvantages, a lubricating oil having none of the above described objections is obtained and both formation of gum or varnish on the piston skirt-and deposition of carbon in the piston ring grooves, as well as corrosion oi alloy bearings, are prevented or inhibited. The following table gives data illustrating the enhanced effectiveness of the combination in preventing piston ring sticking and in inhibiting varnish" i'ormation-the piston discoloration numbcr being a measure of varnish iormation:

- phate in the oil:

I I Piston disctglora- Ring 1 ring tion num er sticking a g g 60hrs. hrs.

Acid refined. Western oil! Hour s I Percent S A E 30 45 700 Ditto-l phosphat 120 0 Ditto+.5% calcium cety- .late+.25%'calciun 1 cetyl 0 70 t en-tra- 'follo zigtable also gives data establishing' the'ii'on corrosiveness of the compounded oil towardcopper-lead and cadmium-silver bearing metal alloys as well as inspections on the used oil showing enhanced stability with the combination'of calciumlan'olate and calcium cetyl phos- Acid refined Western v I oil 5. A. E. 30 f Compounding agent J H o a e None Ca cetyl phosphate Corrosion- 72 hrs.-ing. loss: a

Copper-lead..- 6. 0 Cadmium-silver 0.0 Used oil inspection:

- Visc. increase 8. S. U. 100 F 2m 35 Naphtha insoluble Data obtained in the sam'e type ofcorrosion test with calcium-ocenolate alone *-andin combination with amyltartrate in'lubricating oil are as follows: i

i u. l 1 Acid treated t Acid treated Western oil Western oil +571, cal- +.5 calcium 5 0mm ocenolate ocenolai-c +.2% amyl j tartratc v 1 Corrosion-wt. loss, mus; i Copper-lead 72 hours 126. 4 14. 0 Cadmium-silver 72 hours. 00.1 0.9 Used oil inspections: l

Increase in visc. at 100 F 785 i 400 Neutralization number" 5:31? 5. 02 Naphtha insolubles 211 134,

The following shows the fused oil inspections of the corrosion test with calcium lanolate alone and combination wit h amyl tartrate:

Increase in viscosity at- Ncutrali- Naphtha Oil zation il'lSOlu- J number blcs Acid treated Western oil 535 13 3. 50 I00 D0.+.5% calcium lanolate. 365 9. 3 1. 07 3l8 D0.+.2% aniyl tartratc 5 l3 3. 50 100 Do.+ .5% calcium lanolate +.2% amyl turtrate 7. 4 1.79 28 1 Values approximate.

. In the foregoing engine tests asingle cylinder, 2%" bore and 2 stroke L: n gasoline engine was operated 'under'ex't'remely severe conditions for the-purpose of developing fully piston ring sticking and piston; gumm'ing tendencies under circumstances simulating severe'operating conditions encounteredin'ithe field. O'peration of the motor during tests was continuous at 2,841,065 1600 R. P. M. speed with periodic shutdowns at fifteen-hour intervals for inspection. The jacket temperature was maintained at 375 F. and the sump oil temperature at 220 F. In the above corrosion tests the following method was utilized: Glass tubes 2" in diameter and 20" long were immersed in an oil bath, the temperature of which was automatically controlled to within i1 F. of the test temperature which was 300 F. Approximately 300 cc. of oil under'test was placed in each tube and air was bubbled through it at the rate of liters per hour. Strips of the two types of bearing metal were placed in the oil. In most cases the copper-lead and the cadmium-silver bearing alloys were tested simultaneously in the same sample of oil. The weight loss of each strip was recorded. Before weighing, each strip was washed in petroleum ether and carefully dried. The duration of the test was 72 hours.

It has also been discovered that hydrocarbon .oils containing an inhibitor comprising a metal salt of a substituted acid of phosphorus, such as calcium cetyl phosphate, form a black deposit when contacted with metal surfaces heated to 425 F. or above. The presence of the alcoholatc in an oil containing such metal phosphate salts inhibits the formation of such' deposits. This property of a cooperation between the two ingredients is illustrated by a test in: which a heated metal surface (hot wire) is contacted with the compounded oil at 300 F. and the temperature gradually raised-to 550 F., at which point it is maintained for one hour. In this test the hot wire is partially immersed and partially exposed in air, and the amount of deposition at the oil surface is observed. The following data illustrate the improvements resulting in the above-described test:

Oil Deposit Zllm.

Q wow An additional new result obtained by the combination of inhibitors utilized in this invention comprises increased stability of the oil solution of each of said components. Lubricating oils containing the metal phosphates alone may become cloudy in storage and the metal salts of substituted acids of phosphorus tend to precipitate from the oil solution in the presence of moisture. Some metal alcoholates are subject to precipitation from solution in lubricating oils or cloud formation in the presence of Water. When both the. alcoholate and the phosphate are present in the lubricating oil the solution becomes more stable against precipitation or cloud formation. Thus the metal alcoholates act as a stabilizing agent for the metal salts of the substituted acids of phosphorus and permit the preparation of more concentrated solutions of the salts than might otherwise be feasible.

From the above detailed descriptions it will be apparent that the combinations of ingredients herein disclosed give a new composition having new and highly useful properties. It is immaterial for the purpose of the present invention whether the separate components be new or old. since it is the discovery of the combination of ingredients and the unpredictable properties obtained thereby which comprise applicants contribution to the'art. The compounded lubricants herein disclosed may have one or more advantages depending upon the particular compounds selected, the proportions utilized, and the environment which the lubricating oil is to encounter. It should be observed, for example, that even though a compounded oil-may be somewhat corrosive to copper-lead or cadmium-silver bearing metals, Bab-.

bitt bearings may be little if at all affected by such corrosive action. Hence, compounded oils which may not be particularly desirable for lubrication of copper-lead or cadmium-silver bearings at high temperatures where corrosion becomes a factor of importancemay be highly useful and extremely advantageous in conjunction with the operation of internal combustion engines having bearings of babbitt or other corrosive-resistant bearing metals. The present invention in its broader aspects is therefore not limited to the particular combination of ingredients having all or the greatest number of advantages but embraces various of the less ad vantageous addition agents which will find utility in particular applications where all the possible improvements in the properties may not be required or where the standard of performance may not be so high.

A moderately acid refined naphthenic base lubricating oil is the preferred base oil stock for the compounded lubricants involved herein. The compounding ingredients appear to function more efficiently in such a base oil than in parafflnic oil stocks or highly refined naphthenic oils.

tion is not limited to any particular base, stock since advantages herein disclosed may be obtained, at least to some degree, with various oil stocks, the selection of which will be determined by conditions and service which the compounded lubricant is to encounter.

The proportion of oxidation inhibitors which may be added to mineral lubricating oils according to the principle of the present invention may vary widely depending upon the uses involved and the properties desired. As little as 0.05% by weight of various of the oxidation inhibitors gives measurable improvements. From approximately 0.1% to 2% of the compound may be added to lubricants containing metal alcoholates where stability at high temperature comprises the principal property desired. Solutions containing more than 2% of the compounds in mineral oils may be utilized for various purposes. e. g. for preparing lubricating greases andconcentrates capable of dilution with lubricatin." oils and the like. Likewise, the proportion of metal alcoholates present in the compound d lubricant may vary widely depending upon th uses involved and the properties desired. A little as 0.1% by weight of the alcoholatc give measurable improvement, although from approximately O.25% to approximately 2% alcoholate is preferred where the compounded oil is to be used as a crankcase lubricant for internal combustion engines. As much as 50% or more by weight of various of the alcoholates may be dissolved in mineral oil for the purpose or preparing a concentrate capable of dilution with lubricating oils and the like. Concentrates containing high percentages of the alcoholate and oxidation inhibitor comprise a convenient meth- 0d of handling the ingredients and may he Hs d as addition agents for lubricants in general, as well as for other purposes.

The combination of ingredients of this invention may be present in hydrocarbon oils containing other compounding agents, such as pour point depressants, oiliness agents, extreme pressure addition agents, blooming agents, and compounds for enhancing the viscosity index of the hydrocarbon oil. The invention in its broader aspects embraces mineral hydrocarbon oils containing, in addition the oxidation inhibitor, thickening agents and/or metal soaps in grease-forming proportions or in amounts insufficient to form grease, as in the case of mineral castor machine oils or other compounded liquid lubricants.

While the character of the invention has been described in detail and numerous examples of the composition given, this has been done by way of illustration only and with the intention that no limitation should be tion thereby. It will be apparent to those skilled in the art that numerous modifications and variations of the illustrative examples may be effected in the practice of the invention which is of the scope of the claims appended hereto.

We claim:

1. A composition of matter comprising a hydrocarbon oil, at least about 0.1% by weight based on the oil of a compound of the type formula:

where M is a metal, X is selected from the group consisting of oxygen and sulfur, C is a nonbenzenoid carbon atom, R is an organic radical of hydrocarbon structure, and n may have a to the metal alcohoiate and imposed on the invenvalue of from one to the valence of the metal; and at least about 0.05% by weight based on the oil of an organic hydroxy ester having at least one hydroxyl group not more than two carbon atoms removed from a carboxyl group of said ester.

2. A composition of matter comprising a hydrocarbon oil, at least about 0.1% by weight based on the oil of a compound of the type formula: I

where M is a metal, X is selected from the group consisting of oxygen and sulfur, C is a non-benzenoid carbon atom, R is an organic radical of hydrocarbon structure, and 11. may have a value of from one to the valence of the metal; and at least about 0.05% by weight based on the oil of an organic ester of a polycarboxylic acid having two carboxyl groups no more than two carbon atoms apart.

3. A composition of matter comprising a hydrocarbon oil, at least about 0.1% by weight based on the oil of a compound of the type formula:

where M is a metal, X is selected from the group consisting of oxygen and sulfur, C is a non-benzenoid carbon atom, R is an organic radical of hydrocarbon structure, and 11, may have a value of from" one to the valence of the metal: and at least about 0.05% by weight based on the oil of an alkaline earth organo-borate.

ARTHUR 1.1., LYMAN. LLOYD H. MULIT.

CERTIFICATE OF CORRECTION- 'Patent No. 251 1565.

February 15, 1914A.

ARTHUR L. LYMAN, ET AL.

It is hereby certified that error appears in the printed of the above numbered patent requirin 0nd column,

line 7, for cadmium" read -'-calcium-;

specification g correction as follows: Page 5, secand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this 25rd day of May, A. D. 19%.

(Seal) Leslie Frazer Acting Commissioner of Patents. 

